CN106029209B - Selective Dispensing Modular Control System - Google Patents

Abstract

Systems and methods of selectively controlling a plurality of dosing modules may include receiving data indicative of an exhaust flow rate. The amount of reductant to be dosed may be determined based at least in part on data indicative of an exhaust flow rate. A decomposition delay time may also be determined, and the first dosing module and the second dosing module may be selectively activated. The first dosing module may be selectively activated at a first time and the second dosing module selectively activated at a second time. The second time is based on the first time and the determined decomposition delay time.

Description

Selective Dispensing Modular Control System

Cross References to Related Applications

This application claims the benefit of and priority to US Patent Application Serial No. 14/157,215, filed January 16, 2014, which is incorporated herein by reference in its entirety.

technical field

The present application relates generally to the field of fluid delivery systems for drainage systems. More specifically, the present application relates to fluid delivery systems for selective catalytic reduction (SCR) systems.

background

For internal combustion engines, such as diesel engines, nitrogen oxides (NO _x ) may be emitted in the exhaust. To reduce _NOx emissions, an SCR process can be implemented to convert _NOx compounds into more neutral compounds such as diatomic nitrogen, water or carbon dioxide with the help of catalysts and reducing agents. The catalyst may be included in a catalyst chamber of an exhaust system, for example, a catalyst chamber of a vehicle or power generating device. A reducing agent (eg, anhydrous ammonia, aqueous ammonia, or urea) is typically introduced into the exhaust gas stream prior to introduction into the catalyst chamber. To introduce the reductant into the exhaust gas stream for use in the SCR process, the SCR system may dose or otherwise introduce the reductant through a dosing module that vaporizes or injects the reductant into the exhaust gas upstream of the catalyst chamber. in the discharge piping of the system.

overview

One embodiment relates to a system for selectively dosing a reductant into an exhaust system. The system includes a first dosing module, a second dosing module, and a controller. The controller is configured to receive data indicative of the exhaust flow rate, determine an amount of reductant based at least in part on the data indicative of the exhaust flow rate, and determine a decomposition delay time. The controller is also configured to selectively activate the first dosing module at a first time and selectively activate the second dosing module at a second time. The second time is based on the first time and the decomposition delay time.

Another embodiment relates to a method for selectively dosing a reductant into an exhaust system. The method includes receiving data indicative of an exhaust flow rate, determining an amount of reductant based at least in part on the data indicative of the exhaust flow rate, and determining a decomposition delay time. The method also includes selectively activating the first dispensing module at a first time and selectively activating the second dispensing module at a second time. The second time is based on the first time and the decomposition delay time.

Yet another embodiment involves a non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform a number of operations. The operations include receiving data indicative of an exhaust flow rate, determining an amount of reductant based at least in part on the data indicative of an exhaust flow rate, and determining a decomposition delay time. The operations also include selectively activating the first dispensing module at a first time and selectively activating the second dispensing module at a second time. The second time is based on the first time and the decomposition delay time.

These and other features of the embodiments described herein, together with their organization and manner of operation, will become apparent from the following detailed description when read in conjunction with the accompanying drawings, wherein in all of the several figures described below the same Components have the same reference numerals.

Brief description of the drawings

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, aspects and advantages of the present disclosure will be apparent from the description, drawings, and claims, in which:

1 is a schematic block diagram of an exemplary selective catalytic reduction system with an exemplary reductant delivery system for an exhaust system;

2 is a front view of an exemplary reductant delivery system with two dosing modules for a decomposition chamber;

3 is a front view of another exemplary reductant delivery system with three angularly offset dosing modules for decomposition chambers;

4 is a perspective view of another exemplary reductant delivery system having two axially aligned dosing modules for a decomposition chamber;

Figure 5A is a timing diagram of dispensing by two dispensing modules with a first time delay wherein the dispensing overlaps;

Figure 5B is a timing diagram of dispensing by two dispensing modules with a second time delay in which dispensing does not overlap;

5C is a timing diagram of dispensing by two dispensing modules, the timing diagram having a third time delay, wherein the first dispensing module ends dispensing when the second dispensing module begins dispensing;

6 is a flow diagram of an example process for a controller to control dosing reductant into an exhaust system using a plurality of dosing modules;

Figure 7 is a graph of dosing reductant by two dosing modules at several operating speeds over a time period of one second;

8A is a graph of alternate dosing of reductant by two dosing modules at a first operating speed over a two second time period;

Figure 8B is a graph of alternate dosing of reductant by two dosing modules at another operating speed over a two second time period;

Figure 8C is a graph of alternate dosing of reductant by two dosing modules at yet another operating speed over a two second time period;

Figure 8D is a graph of alternate dosing of reductant by two dosing modules at yet another operating speed over a two second time period;

9 is a flow diagram of another example process for a controller controlling dosing reductant into an exhaust system using a plurality of dosing modules;

Figure 10 is a graph of dosing reductant by two dosing modules at several operating speeds over a time period of one second;

11A is a graph of alternate dosing of reductant by two dosing modules at a first operating speed over a two second time period;

11B is a graph of alternate dosing of reductant by two dosing modules at another operating speed over a two second time period;

11C is a graph of alternate dosing of reductant by two dosing modules at yet another operating speed over a two second time period; and

FIG. 11D is a graph of alternate dosing of reductant by two dosing modules at yet another operating speed over a two second time period;

It should be appreciated that some or all of the drawings are schematic for purposes of illustration. The drawings are provided for the purpose of illustrating one or more embodiments, with the express understanding that they will not be used to limit the scope or meaning of the claims.

A detailed description

I. Overview

In some instances, such as, for example, very large trucks, mining equipment, locomotives, etc., a large amount of horse power provided by an internal combustion engine, such as a diesel engine, may be required or desired. In order to meet such demands, large internal combustion engines such as diesel engines can be developed. However, as the size and power of engines increase, the amount of nitrogen oxide (NO _x ) compounds produced by such engines may also increase. _NOx compounds may be emitted into the exhaust. To reduce _NOx emissions, an SCR process can be implemented to convert _NOx compounds into more neutral compounds such as diatomic nitrogen, water or carbon dioxide with the help of catalysts and reducing agents. A catalyst may be included in a catalyst chamber of the exhaust system. A reducing agent (eg, anhydrous ammonia, aqueous ammonia, or urea) is typically introduced into the exhaust gas stream prior to introduction into the catalyst chamber. However, as engine size increases, the amount of reductant required to reduce _NOx compounds likewise increases. Therefore, large quantities of reductants may need to be introduced into the emissions system to effectively reduce NO _x compounds. In some embodiments, the rate at which reductant is dosed into the exhaust system may be increased. However, some dosing modules may have a maximum dosing speed capability that may not meet the required amount of reductant.

In some embodiments, the system can selectively control reductant dosing from multiple dosing modules in the system either staged in series or located in a single decomposition chamber to remove _NOx compounds from the exhaust gas. The system may utilize a process involving the selective use of two or more dosing modules to dispense reductant into the decomposition chamber to maximize the efficiency of dosing to remove _NOx compounds from the exiting exhaust gas stream. The system can control two or more dosing modules located in the same decomposition chamber in the same system for dosing reducing agent or dosing consecutively in the system. The timing and selection of dosing reductant can be determined by the logic of the control controller to maximize the efficiency of dosing, maximize the efficiency of reductant use, minimize dosing from two or more dosing in the same chamber or system Possible negative factors (eg deposit formation) and/or over-allocation of modules.

This process may allow coordinated dosing of reductant at various intervals between two or more dosing modules for dosing reductant within the same decomposition chamber or within the same system. This process may allow dosing of reductant to be controlled based on exhaust flow rate by selectively controlling the dosing of each dosing module into the exhaust gas stream.

In some embodiments, each of the dosing modules can simultaneously dispense an amount of reductant over a period of time to satisfy a desired amount of reductant. That is, within a given period, such as one second, each of the plurality of dosing modules may dispense reductant for a predetermined period of time (e.g., 100 milliseconds (ms)) within the given period to In the exhaust system, the total amount of reductant dispensed by the dispensing module meets the required amount of reductant. In some embodiments, two, three, four or more distribution modules may be used.

In other embodiments, the dosing modules may dose at different times based on the delay time between each dosing module. That is, within a given period, such as one second, a first dosing module of the plurality of dosing modules may dispense reductant into the exhaust system for a predetermined period of time (eg, 100 ms) within the given period . A second dosing module of the plurality of dosing modules may dispense reductant into the exhaust system for a predetermined period of time (eg, 100 ms) within a given period. The dosing by the first dosing module and the second dosing module can be shifted by a time delay. The predetermined time period of the first dosing module and the second dosing module may be determined such that the total amount of reductant dispensed by the dosing modules meets the required amount of reductant. In some embodiments, two, three, four or more distribution modules may be used. The time delay between modules may be determined such that the dosing through several modules is substantially evenly spaced within a given period.

In still other embodiments, the first dosing module can be used to perform dosing until the required amount of reductant exceeds the maximum amount that the first dosing module can dispense in a given period. The second dosing module can then be used to provide additional reductant up to the required amount of reductant. In some embodiments, two, three, four or more distribution modules may be used. Thus, if the required amount of reductant exceeds the maximum amount that can be provided by the first and second dosing modules, the third or further dosing modules may be used to provide additional reductant.

In some embodiments, the dosing modules may be cycled sequentially such that the duty cycle of each dosing module in the plurality of dosing modules is substantially the same over N operating cycles, where N is the number of dosing modules.

Although an overview of controlling multiple dosing modules has been given above, the following are various concepts related to methods, apparatus and systems for introducing reductant to an exhaust system using multiple dosing modules and for using multiple dosing modules to introduce A more detailed description of embodiments of methods, apparatus and systems for introducing a reductant into an exhaust system. The various concepts introduced above and discussed in greater detail below can be implemented in any of a variety of ways, as the described concepts are not limited to any particular manner of implementation. Specific implementation and application examples are provided primarily for purposes of illustration.

II. Review of Selective Catalytic Reduction Systems

FIG. 1 depicts a selective catalytic reduction system 100 with an exemplary reductant delivery system 110 for an exhaust system 190 . The selective catalytic reduction system 100 includes a diesel particulate filter (DPF) 102 , a reductant delivery system 110 , a decomposition chamber or reactor 104 , and an SCR catalyst 106 .

DPF 102 is configured to remove particulate matter, such as soot, from exhaust gas flowing in exhaust system 190 (indicated by arrow 192 ). DPF 102 includes an inlet through which exhaust gas is received and an outlet through which exhaust gas exits after having substantially filtered particulate matter from the exhaust gas and/or converted the particulate matter to carbon dioxide.

The decomposition chamber 104 is configured to convert a reductant, such as urea, ammonia, or diesel exhaust fluid (DEF), into ammonia. As will be described in greater detail herein, the decomposition chamber 104 includes a reductant delivery system 110 having a plurality of dosing modules 112 configured to dispense reductant into the decomposition chamber 104 . In some embodiments, urea, ammonia, and DEF are injected upstream of the SCR catalyst 106 . The reductant droplets then undergo evaporation, thermal decomposition, and hydrolysis processes to form gaseous ammonia within exhaust system 190 . Decomposition chamber 104 includes an inlet in fluid communication with DPF 102 to receive exhaust gas including NO _x emissions and an outlet for flow of exhaust gas, NO _x emissions, ammonia, and/or remaining reductant to SCR catalyst 106 .

The SCR catalyst 106 is configured to assist in the reduction of NO _x emissions to diatomic nitrogen, water, and/or carbon dioxide by accelerating the NO _x reduction process between ammonia and NO _x of the exhaust gas. The SCR catalyst 106 includes an inlet in fluid communication with the decomposition chamber 104 and an outlet from which exhaust gas and reductant are received.

Emissions system 190 may also include a diesel oxidation catalyst (DOC) in fluid communication with exhaust system 190 to oxidize hydrocarbons and carbon monoxide in exhaust gases (eg, downstream of SCR catalyst 106 or upstream of DPF 102 ).

As noted above, the decomposition chamber 104 includes a plurality of dosing modules 112 mounted to the decomposition chamber 104 such that the plurality of dosing modules 112 can dispense reductants such as urea, ammonia, or DEF to the exhaust system. 190 in the flowing exhaust gas. The plurality of distribution modules 112 may each include an insulator 114 interposed between a portion of the distribution module 112 and a portion of the decomposition chamber 104 in which the distribution module 112 is installed. A plurality of dosing modules 112 are fluidly coupled to one or more reductant sources 116 . In some embodiments, each dosing module 112 may be fluidly coupled to a corresponding reductant source 112 or the plurality of dosing modules 112 may be coupled to the same reductant source 116 . In some embodiments, a pump (not shown) may be used to pressurize the reductant source 116 for delivery to the dosing module 112 .

The plurality of dosing modules 112 is also electrically or communicatively coupled to a controller 120 . As will be described in greater detail herein, controller 120 is configured to control each dosing module 112 . The controller 120 may include a microprocessor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), etc. or a combination thereof. Controller 120 may include memory, which may include, but is not limited to, electronic memory, optical memory, magnetic memory, or any other storage or transmission device capable of providing program instructions to a processor, ASIC, FPGA, or the like. The memory may include memory chips, electrically erasable programmable read only memory (EEPROM), erasable programmable read only memory (EPROM), flash memory, or any other suitable memory from which controller 120 can read instructions. Instructions may include code generated in any suitable programming language.

III. Exemplary Configurations of Reductant Delivery Systems

FIG. 2 depicts an exemplary reductant delivery system 210 for a decomposition chamber 200 having two dosing modules 212 mounted to the decomposition chamber 200 . The dosing modules 212 may each include an insulator 214 interposed between a portion of the dosing module 212 and a portion of the decomposition chamber 200 where the dosing module 212 is installed. In this example, the dosing modules 212 are mounted to the decomposition chamber 200 at substantially the same longitudinal axis position but at different angular positions around the decomposition chamber 200 . As shown in FIG. 2 , the dosing modules 212 are positioned opposite each other on the left side 202 and the right side 204 of the decomposition chamber 200 . In other embodiments, the dosing modules 212 may be located at other angular positions relative to each other. For example, a dosing module 212 may be located on the left side 202 towards the top of the decomposition chamber 200 at 60 degrees from the vertical axis, and another dosing module 212 may be located on the right side 202 towards the top of the decomposition chamber 200 at 60 degrees from the vertical axis , thereby forming a generally V-shaped orientation relative to each other. Of course, any other positioning of the dispensing module 212 about the decomposition chamber 200 may be used.

FIG. 3 depicts another exemplary reductant delivery system 310 for a decomposition chamber 300 having three dosing modules 312 mounted to the decomposition chamber 300 . The distribution modules 312 may each include an insulator 314 interposed between a portion of the distribution module 312 and a portion of the decomposition chamber 300 where the distribution module 312 is installed. In this example, the dosing modules 312 are mounted to the decomposition chamber 300 at substantially the same longitudinal axis position but at different angular positions around the decomposition chamber 300 . As shown in FIG. 3 , the dispensing modules 312 are equally spaced around the decomposition chamber 300 , eg, at 120 degree intervals, with one dispensing module 312 located at the top 306 of the decomposition chamber 300 . Of course, the dosing modules 312 may be positioned at other angular positions relative to each other. Also, it should be understood that more than three distribution modules 312 may be used. For example, four distribution modules, five distribution modules, etc.

FIG. 4 depicts another exemplary reductant delivery system 410 for a decomposition chamber 400 having two axially aligned dosing modules 412 mounted to the decomposition chamber 400 . The distribution modules 412 may each include an insulator 414 interposed between a portion of the distribution module 412 and a portion of the decomposition chamber 400 where the distribution module 412 is installed. In this example, dosing modules 412 are mounted to decomposition chamber 400 at substantially the same angular position but at different longitudinal axis positions. It should be understood that more than three distribution modules 312 may be used. For example, four distribution modules, five distribution modules, etc.

In some embodiments, the distribution modules described herein can be both axially and angularly offset (ie, a combination of FIGS. 2-3 and 4 ). Also, it should be understood that any number of distribution modules may be used. For example, four distribution modules, five distribution modules, etc.

IV.

As noted above, a plurality of distribution modules, such as distribution module 112 of FIG. 1 , is electrically or communicatively coupled to a controller, such as controller 120 of FIG. 1 . Described in more detail herein is a process that can be achieved by a controller controlling the dispensing of a plurality of dispensing modules.

Figures 5A-5C depict various dosing schemes for two dosing modules. It should be understood that the following scheme can also be applied to three, four, five or more distribution modules. Figure 5A depicts a timing diagram 500 for dosing by two dosing modules with a first time delay 510 where the dosing overlaps. As shown, the first dosing module continues dosing for a first time period 512 . The second dosing module continues dosing for a second time period 514 that is offset by the first time delay 510 . As shown, the second dosing module starts dosing before the first dosing module stops dosing. Thus, a first time period 512 of dosing by the first dosing module overlaps a second time period 514 of dosing by the second dosing module.

Figure 5B depicts a timing diagram 500 for dosing by two dosing modules with a second time delay 520 where the dosing does not overlap. As shown, the first dosing module continues dosing for a first time period 522 . The second dosing module continues the dosing for a second time period 524 that lapses by the second time delay 520 . As illustrated, the second dosing module starts dosing after the first dosing module has stopped dosing. Thus, the first time period 522 for dosing by the first dosing module does not overlap the second time period 524 for dosing by the second dosing module.

FIG. 5C depicts a timing diagram 500 for dispensing by two dosing modules with a third time delay 530 where the first dosing module ends dosing when the second dosing module begins dosing. As shown, the first dosing module continues dosing for a first time period 532 . The second dosing module continues the dosing for a second time period 534 that elapses with a second time delay 530 . As shown, when the first dispensing module stops dispensing, the second dispensing module starts dispensing. Thus, a first time period 532 of dosing by the first dosing module is "contiguous" with a second time period 534 of dosing by the second dosing module.

FIG. 6 is a flow diagram of an example process 600 for controller-controlled dosing of reductant into an emissions system using a plurality of dosing modules. At 602 , process 600 includes receiving data representing a discharge flow rate. Data representing exhaust flow rates may include and/or be determined based on engine speed selection, flow rate measurements, or a combination of calculated and measured elements including air mass flow, fuel flow, temperature, pressure, rate of change, or a combination of some or all of these terms, etc. Data representing discharge flow rates may be communicated to one or more sensors.

At 604, the amount of reductant may be determined by the controller. The amount of reductant may be determined based at least in part on data indicative of exhaust flow rate. For example, the amount of reductant may be determined based on a selection of engine speed (eg, engine operating speed at a known speed load point) or engine operating parameters. In other embodiments, the amount of reductant may be determined based on other data in addition to or instead of data indicative of exhaust flow rate. The amount of reductant may be based on a dosing rate of one or more dosing modules, exhaust gas temperature, and the like.

At 606, the decomposition delay time may be determined by the controller. The split delay time is the delay between a dosing module, for example a first dosing module and a second dosing module. In some embodiments, the decomposition delay time can be determined based on: the dosing rate of the dosing module, the exhaust gas temperature, the exhaust flow rate, the evaporative cooling rate of the reductant, the heat transfer environment, the current temperature of the system, and/or can be determined for each conditions (eg, for various engine speed load points, exhaust flow rates and temperatures, etc.) and measured and calculated parameters. The decomposition delay time can be determined such that decomposition can occur while avoiding deposition and providing _NH3 to the catalyst as close as possible to the dosing time. If the delay time is too short, deposits may form in the exhaust system. If the delay time is too long, the system may not be able to dispense the required amount of reductant. In some implementations, the decomposition delay time may be in 100 ms intervals. In some embodiments, the ratio of the breakup delay time to the frequency of the dosing module pulses may be 1/10 ^th to 6/10 ^ths (eg, for a 1 Hz dosing module pulse, the breakup delay time may be between 100 ms and 600 ms). Of course, other delay times may be used.

In still further embodiments, the split delay time may be determined for multiple dosing modules. For example, in a system with three dosing modules, the split delay time may be determined between dosing to the first and second module and between dosing to the second and third module.

At 608, the first dosing module is selectively activated by the controller, and at 610, the second dosing module is selectively activated by the controller. The first dosing module may be selectively activated at a first time and the second dosing module is selectively activated at a second time, the second time being determined based on the first time and the determined decomposition delay time. That is, the determined decomposition delay time is used to shift the time of the activation of the second dosing module relative to the first dosing module.

In some embodiments, the selective activation of the first dispensing module and the second module may include selectively activating the second dispensing module at a second time (e.g., overlapping, such as shown in FIG. 5A ) when the first dispensing module is activated. out). In additional embodiments, the selective activation of the first dispensing module and the second dispensing module may include selectively activating the second dispensing module (e.g., non-overlapping, such as shown in FIG. ). In yet other embodiments, the selective activation of the first dispensing module and the second module may include selectively activating the second dispensing module (e.g., adjacent, such as shown in FIG. 5C ) when the first dispensing module is deactivated. out).

In some implementations, the third dosing module can be selectively activated by the controller at 612 . The third dispensing module is selectively activatable at a third time based on the first time, the second time, and the split delay time. Additional dosing modules can be activated by the controller in a similar process as needed. In still further embodiments, for example, if a dosing module fails or is otherwise rendered inoperable, the controller may be configured to keep dosing with any remaining dosing modules such that the reductant is still dispensed, But are rationed at a much smaller level. Thus, for example, a vehicle incorporating such an engine may "limp home", eg, to a location where the inoperable distribution module may be repaired and/or replaced.

FIG. 7 is a graph 700 of dosing reductant by two dosing modules over several operating engine speeds over a time period of one second. The first dosing module doses reductant at a first operating speed for a first time period 702 . The second dosing module doses reductant for a second time period 704 after a first breakdown delay time, eg, 500 ms as shown. The first dosing module and the second dosing module may continue to dosing alternately based on the first split delay. In the example shown, dosing by the first dosing module for the first time period 702 and dosing by the second dosing module for the second time period 704 do not overlap.

The first dosing module doses reductant at the second operating speed for a first time period 712 . The second dosing module doses the reductant for a second time period 714 after the decomposition delay time of 500 ms. The first dosing module and the second dosing module may continue to dosing alternately based on the decomposition delay time. The first dosing module doses reductant at the third operating speed for the first time period 722 . The second dosing module doses the reductant for a second time period 724 after the decomposition delay time of 500 ms. The first dosing module and the second dosing module may continue to dosing alternately based on the decomposition delay time. The first dosing module doses reductant at a fourth operating speed for a first time period 732 . The second dosing module doses the reductant for a second time period 734 after the decomposition delay time of 500 ms. The first dosing module and the second dosing module may continue to dosing alternately based on the decomposition delay time.

The first dosing module doses reductant at the fifth operating speed for a first time period 742 . The second dosing module doses reductant for a second time period 744 after a second breakdown delay time, eg, shown as approximately 480 ms. In this example, the second decomposition delay time is reduced based on the amount of reductant required by the second dosing module to be in operation for longer than 500 ms to meet the fifth operating speed. Thus, in the example shown, dosing by the first dosing module for a first time period 742 overlaps dosing by the second dosing module for a second time period 744 . The first dosing module and the second dosing module may continue to dosing alternately based on the second decomposition delay time.

The first dosing module doses reductant at the sixth operating speed for a first time period 752 . The second dosing module doses reductant for a second time period 754 after a third decomposition delay time, eg, shown as approximately 300 ms. The first dosing module and the second dosing module may continue to dosing alternately based on the third decomposition delay time. The first dosing module doses reductant at the seventh operating speed for a first time period 762 . The second dosing module doses reductant for a second time period 764 after a fourth decomposition delay time, eg, shown as approximately 120 ms. The first dosing module and the second dosing module may continue to dosing alternately based on the fourth decomposition delay time.

Figures 8A-8D depict this alternating dosing of the first and second dosing modules over a two second time period. 8A depicts a graph 800 of alternate dosing of reductant by two dosing modules at a first operating speed over a two second time period. 8B depicts a graph 810 of alternate dosing of reductant by two dosing modules at another operating speed over a two second time period. 8C depicts a graph 820 of alternate dosing of reductant by two dosing modules at yet another operating speed over a two second time period. FIG. 8D depicts a graph 830 of alternate dosing of reductant by two dosing modules at another operating speed over a two second time period.

9 is a flowchart of an example process 900 for controller-controlled dosing of reductant into an emissions system using a plurality of dosing modules. At 902 , process 900 includes receiving data representing a discharge flow rate. Data representing exhaust flow rates may include and/or be determined based on: engine speed selection, flow rate measurements, or a combination of calculated and measured elements (including air mass flow, fuel flow, temperature, pressure), changes in these parameters rate, or a combination of some or all of these parameters, etc. Data representing discharge flow rates may be communicated to one or more sensors.

At 904, the amount of reductant may be determined by the controller. The amount of reductant may be determined based at least in part on data indicative of exhaust flow rate. For example, the amount of reductant may be determined based on a selection of engine speed (eg, engine operating speed at a known speed load point) or engine operating parameters. In other embodiments, the amount of reductant may be determined based on other data in addition to or instead of data indicative of exhaust flow rate. The amount of reductant may be based on a dosing rate of one or more dosing modules, discharge temperature, etc.

At 906, the first dosing module and the second dosing module are selectively activated by the controller. In some embodiments, the first dosing module is selectively activatable to provide an amount of reductant for a first time period. A second dosing module is selectively activatable to provide an amount of reductant for a second time period. Accordingly, the first dosing module and the second dosing module may alternately provide the amount of reductant during the first time period and the second time period. In some instances, such as when the first dosing module may not itself be able to meet the amount of reductant, the second dosing module may be selectively activated with the first dosing module for a period of time to supplement the amount of reductant provided by the first dosing module. rationing. At 908, in some implementations, a third dosing module can be selectively activated by the controller. The third dispensing module is selectively activatable at a third time based on the first time, the second time, and the split delay time. Additional dosing modules can be activated by the controller in a similar process as required.

FIG. 10 is a graph 1000 of dosing reductant by two dosing modules over several operating engine speeds over a time period of one second. The first dosing module doses reductant at a first operating speed for a first time period 1002 . The first dosing module doses reductant at a second operating speed for a second time period 1012 . The first dosing module doses reductant at a third operating speed for a third time period 1022 . The first dosing module doses reductant at a fourth operating speed for a fourth time period 1032 .

The first dosing module doses reductant at the fifth operating speed for a fifth time period 1042, which is a full one-second time period. The second dosing module may be selectively activated to dispense reductant for a second time period 1044 to supplement dosing by the first dosing module. Both the first dosing module and the second dosing module may be selectively activated at the same time, or in some embodiments, the selective activation of the second dosing module may be delayed by a time delay. The first dosing module doses reductant at the sixth operating speed for a fifth time period 1042 . The second dosing module may be selectively activated to dispense reductant for a second time period 1054 to supplement dosing by the first dosing module. Both the first dosing module and the second dosing module may be selectively activated at the same time, or in some embodiments, the selective activation of the second dosing module may be delayed by a time delay. The first dosing module doses reductant at the seventh operating speed for a fifth time period 1042 . The second dosing module may be selectively activated to dose reductant for a third time period 1064 to supplement dosing by the first dosing module. Both the first dosing module and the second dosing module may be selectively activated at the same time, or in some embodiments, the selective activation of the second dosing module may be delayed by a time delay.

11A-11D depict alternating dosing by a first dosing module and a second dosing module over a two second time period. 11A depicts a graph 1100 of alternate dosing of reductant by two dosing modules at a first operating speed over a two second time period. FIG. 11B depicts a graph 1110 of alternately dosing reductant through two dosing modules at another operating speed over a two-second time period. FIG. 11C depicts a graph 1120 of reductant dosing alternately by two dosing modules at yet another operating speed over a two-second time period. FIG. 11D depicts a graph 1130 of alternate dosing of reductant by two dosing modules at yet another operating speed over a two-second time period.

Embodiments of the subject matter and operations described in this specification may be implemented in digital circuitry or in computer software embodied on tangible media, firmware, or hardware including the structures disclosed in the specification and their structural equivalents, or in implemented in a combination of one or more. The subject matter described in this specification can be implemented as one or more computer programs, that is, one or more computer programs encoded on one or more computer storage media for execution by or to control the operation of digital processing means. A computer program instruction module. Alternatively or in addition, the program instructions may be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical and/or electromagnetic signal, which is generated to encode for transmission to a suitable receiving device for information for execution by data processing means. A computer storage medium may be or may be included in a computer readable storage device, a computer readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Furthermore, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium may also be, or be included in, one or more separate components or media (eg, multiple CDs, disks, flash drives, or other storage devices). Thus, computer storage media is both tangible and non-transitory.

The operations described in this specification may be performed by data processing apparatus on the basis of data stored on one or more computer-readable storage devices or received from other sources.

The term "controller" includes all kinds of devices, devices and machines that process data, including, for example, programmable processors, computers, systems based on a single chip or multiple chips, part of a programmable processor, or combinations of the above . A device may include dedicated logic circuitry, such as an FPGA or an ASIC. In addition to hardware, the means may also include code for creating an execution environment for the computer program in question, for example, constituting processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime, a virtual machine, or one of A combination of multiple codes. The apparatus and execution environment can implement infrastructures of various computing models, such as distributed computing infrastructures and grid computing infrastructures.

A computer program (also called a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted, declarative, or procedural languages, and a computer program can include Deployment in any form, as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in part of a file that holds other programs or data (for example, one or more scripts stored in markup language text), in a single file dedicated to the program in question, or in multiple in a collaborative file (for example, a file that stores one or more modules, subroutines, or portions of code).

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to specific implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Furthermore, although features above may be described as functioning in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be deleted from the combination and claimed A combination may involve subcombinations or variations of subcombinations.

Similarly, while operations are depicted in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations should be performed in order achieve the desired result. In some cases, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described components and systems may generally be incorporated into In a single product or packaged into multiple products embodied on a tangible medium.

As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning consistent with common and accepted usage by those of ordinary skill in the art to which the disclosed subject matter belongs . Those of skill in the art who review this disclosure should understand that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be construed to indicate that insubstantial or insignificant modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims . Furthermore, it should be noted that limitations in the claims should not be construed as constituting "means-plus-function" limitations under US Patent Law, where the term "means" is not used.

The terms "coupled", "connected" and similar terms used herein mean that two components are connected directly or indirectly to each other. Such connections may be fixed (eg, permanent) or mobile (eg, removable or releasable). Such connection may be made using two parts or two components integrally forming a single unitary body and any additional intermediate parts or using two parts or two parts connected to each other and any additional intermediate parts.

As used herein, the terms "fluidly coupled," "in fluid communication," and similar terms mean that two parts or objects have a path formed between the two parts or objects in which, for example, water, air, a gaseous reducing agent, Fluids such as gaseous ammonia may flow with or without intervening components. Examples of fluid couplings or configurations for enabling fluid communication may include tubes, channels, or any other suitable components for enabling fluid flow from one component or object to another.

It is important to note that the construction and arrangement of the systems shown in the various exemplary embodiments are illustrative in nature and not restrictive. Protection is desired for all changes and modifications that come within the spirit and/or scope of the described embodiments. It should be understood that some features may not be required and that embodiments lacking the individual features are considered to be within the scope of the present application, which scope is defined by the following claims. When reading the claims, it is intended that when words such as "a(a)", "an", "at least one" or "at least a portion" are used, there is no limitation of the claim to only one item intent unless specifically stated to the contrary in the claims. When the language "at least a portion" and/or "a portion" is used, the item may include a portion and/or the entire item unless specifically stated to the contrary.

Claims (24)

1. a kind of system for being used to be selectively dispensed to reducing agent in exhaust system, the system include：

First dispensing module；

Second dispensing module；With

Controller, the controller are configured to：

The data for representing discharge speed are received,

It is based at least partially on and represents that the data of the discharge speed determine the amount of reducing agent, it is determined that time delay is decomposed,

The first dispensing module is optionally activated in the very first time, and

Activate the second dispensing module in the second time selectivity, second time is based on very first time and described Decompose time delay.

2. system according to claim 1, wherein, reducing agent is diesel exhaust fluid.

3. system according to claim 1, wherein, optionally activate institute while the first dispensing module is activated State the second dispensing module.

4. system according to claim 1, wherein, disabled afterwards described in optionally activation in the first dispensing module Second dispensing module.

5. system according to claim 1, wherein, when optionally disabling the first dispensing module, optionally Activate the second dispensing module.

6. system according to claim 1, in addition to：

3rd dispensing module；

Wherein, the controller is configured to activate the 3rd dispensing module in the 3rd time selectivity, when the described 3rd Between be based on the very first time, second time and the decomposition time delay.

7. system according to claim 1, wherein, the first dispensing module and the second dispensing module are mounted to make The first dispensing module and the second dispensing module by reducing agent with being given in decomposition chamber.

8. system according to claim 7, wherein, the first dispensing module and the second dispensing module are arranged on institute State on the relative side of decomposition chamber.

9. system according to claim 1, wherein, the data for representing discharge speed are engine speeds.

10. system according to claim 1, wherein, the controller is configured to optionally swash in the very first time The first dispensing module living activates described second with the reducing agent of the amount of dispensing first and in second time selectivity Dispensing module with the reducing agent of the amount of dispensing second, the reducing agent of the reducing agent of first amount and second amount and be approximately equal to The amount of identified reducing agent, wherein, the first dispensing module and the second dispensing module optimize in the exhaust system NO_xThe reduction of compound.

11. a kind of method for being used to be selectively dispensed to reducing agent in exhaust system, methods described include：

The data for representing discharge speed are received at controller；

It is based at least partially on using the controller and represents that the data of the discharge speed determine the amount of reducing agent；

Determine to decompose time delay using the controller；

The first dispensing module is optionally activated in the very first time using the controller；With

The second dispensing module is activated in the second time selectivity using the controller, second time is based on described first Time and the decomposition time delay.

12. according to the method for claim 11, wherein, reducing agent is diesel exhaust fluid.

13. the method according to claim 11, in addition to：

After the second dispensing module is optionally activated first dispensing is optionally disabled using the controller Module.

14. the method according to claim 11, in addition to：

Before the second dispensing module is optionally activated the first dispensing mould is selectively disabled using the controller Block.

15. the method according to claim 11, in addition to：

When optionally activating the second dispensing module, the first dispensing mould is selectively disabled using the controller Block.

16. the method according to claim 11, in addition to：

The 3rd dispensing module is activated in the 3rd time selectivity using the controller, the 3rd time is based on described first Time, second time and the decomposition time delay.

17. according to the method for claim 11, wherein, the first dispensing module is selectively activated in the very first time The reducing agent of the amount of dispensing first, and going back in second time selectivity activation the second amount of the second dispensing module dispensing The reducing agent of former agent, the reducing agent of first amount and second amount and reducing agent determined by being approximately equal to amount, wherein, The first dispensing module and the second dispensing module optimize NO in the exhaust system_xThe reduction of compound.

18. a kind of computer readable medium of non-transient, the computer readable medium storage instruction of the non-transient, when this Instruction causes one or more of computing devices to operate when being executed by one or more processors, the operation includes：

Receive the data for representing discharge speed；

It is based at least partially on and represents that the data of the discharge speed determine the amount of reducing agent；

It is determined that decompose time delay；

The first dispensing module is optionally activated in the very first time；And

The second dispensing module is activated in the second time selectivity, second time is based on the very first time and the decomposition Time delay.

19. the computer readable medium of non-transient according to claim 18, the non-transient it is computer-readable Medium storing instructs, and the instruction causes one or more of computing devices to operate, and the operation also includes：

The first dispensing module is optionally disabled after the second dispensing module is optionally activated.

20. the computer readable medium of non-transient according to claim 18, the non-transient it is computer-readable Medium storing instructs, and the instruction causes one or more of computing devices to operate, and the operation also includes：

Before the second dispensing module is optionally activated first dispensing is optionally disabled using the controller Module.

21. the computer readable medium of non-transient according to claim 18, the non-transient it is computer-readable Medium storing instructs, and the instruction causes one or more of computing devices to operate, and the operation also includes：

When optionally activating the second dispensing module, the first dispensing mould is optionally disabled using the controller Block.

22. the computer readable medium of non-transient according to claim 18, the non-transient it is computer-readable Medium storing instructs, and the instruction causes one or more of computing devices to operate, and the operation also includes：

The 3rd dispensing module is activated in the 3rd time selectivity using the controller, the 3rd time is based on described first Time, second time and the decomposition time delay.

23. the computer readable medium of non-transient according to claim 18, wherein, in very first time selectivity Ground activates the reducing agent of the operation amount of dispensing first of the first dispensing module, and is activated in second time selectivity The reducing agent of the operation amount of dispensing second of the second dispensing module, the reduction of the reducing agent of first amount and second amount Agent and reducing agent determined by being approximately equal to amount, wherein, the first dispensing module and the second dispensing module optimization institute State NO in exhaust system_xThe reduction of compound.

24. the computer readable medium of non-transient according to claim 18, the non-transient it is computer-readable Medium storing instructs, and the instruction causes one or more of computing devices to operate, and the operation also includes：

Determine that the first dispensing module or the second dispensing module are inoperable；And

Limp-home mode is activated, wherein the limp-home mode continues to activate the first remaining dispensing module or second matched somebody with somebody To module.